[128] Stimulated by the
high-level interest in Rex from his March 1955 trip to ARDC
Headquarters, Philip Richie returned to his procurement duties at
Wright Field's power plant laboratory expecting to let a contract on
Rex within a month.35 This was not to be. In fact, what followed was an
extraordinary series of proposals by Rae and Garrett on the one hand
and revisions of statements of work by personnel of the power plant
laboratory on the other, with many negotiations between the two
groups. These actions reverberated up and down the line, affecting
virtually every level of management in Air Force research and
development as far as the Assistant Secretary. At the root of the
problem was a fundamental difference in approach between Rae and
Garrett on the one hand and Appold and his associates at the power
plant laboratory on the other. Rae insisted on a contract for the
complete airplane powered by his turbine engine. This differed from
the usual Air Force practice. An airframe manufacturer usually is the
prime contractor for an airplane, including its tanks and fuel
system, with the engine furnished either by the government or by an
engine manufacturer, as a subcontractor to the airframe manufacturer.
Garrett, as a manufacturer of aircraft components and small turbine
machinery, had often been a subcontractor but went along with Rae's
desire to obtain the complete aircraft contract. Obviously, Garrett
intended, at some point, to either license or work jointly with an
airframe manufacturer.

The Air Force, on the other hand, respected
Rae's position as the originator of a novel solution to a difficult
problem, but never viewed either him or Garrett as potential
contractors for an entire airplane. The Air Force became extremely
interested in hydrogen as a fuel and the Rex engine as a means for
reaching very high altitudes, but was not fully convinced that either
was practical. For these reasons, the power plant laboratory, not the
weapon systems directorate, took the lead in initiating the purchase
requests to explore the Rex concept and in dealing with Rae and
Garrett. The laboratory wanted a step-by-step approach to determine
the feasibility of using hydrogen and the Rex engine before
initiating a large development effort. Necessary steps included a
study of engine cycles, selection of the optimum cycle, and
[129]
experimental work on selected components including the fuel tank. The
laboratory would review the work at each step before approving the
next. This logical and conservative approach was irksome to Rae and
Garrett, who were convinced they had a great idea and wanted to move
fast to capitalize on it. They did decide, however, to propose a
series of engines using hydrogen.

The negotiations with Garrett began on 20
April 1955 when Rae and Snow presented the Garrett proposal to Wright
Field and followed it up two days later with a report. Their proposal
went so far beyond what the laboratory had intended that one listener
commented that it covered PR 303 "like the state of Texas covers
Rhode Island."36 Included in the proposal were three types of
hydrogen-fueled engines called Rex I, II, and
III.37 All were jet propulsion engines; the propeller had
disappeared. Rex I used liquid hydrogen and liquid oxygen to drive
multiple turbines, with the hydrogen-rich exhaust gases dumped
overboard. It was the same turbine system as Rae's original Rex I
(pp.119-121). The shaft power from the turbines was used to drive
a fan which compressed incoming air (fig. 31,
top). Thrust was obtained by expanding and accelerating the air
through the nozzle.

Rex II was similar to Rex I except that the
hydrogen-rich exhaust gases from the turbines were burned in the air
in the afterburner (fig.
31, bottom). Rex II was essentially
the same concept as a turborocket (p.122).

Rex III was quite different from the other two
engines. Liquid oxygen was not used, and the hydrogen served two
different functions. First, heated hydrogen alone was used to drive
the turbines; and second, the hydrogen was burned with air to provide
the heat for the first function. This sounds like a man lifting
himself by his bootstraps, but it works (fig. 32).
Hydrogen from the tank is raised to a high pressure by a pump and
passes through a heat exchanger where it is heated to a sufficiently
high temperature to drive the first turbine. After leaving the
turbine, it is reheated in a second heat exchanger and the process
repeated for the third turbine. After the third turbine, the hydrogen
enters a combustion chamber where it mixes with part of the engine
air and burns fuel-rich. The hot combustion gases provide the source
of heat for the three exchangers that heat the incoming hydrogen.
After the third heat exchanger, the hydrogen-rich gases are injected
and burned in the main air stream of the engine in the afterburner.
The three turbines drive the compressors for the incoming engine air
and the air used to burn the hydrogen.

The scope of the Garrett proposal of April
1955 became an issue between the company and the power plant
laboratory, as negotiations continued. In early May, Rae complained
to Brig. Gen. V.R. Haugen, director of laboratories at Wright Air
Development Center, that the power plant laboratory had emasculated
his program. Haugen investigated and satisfied himself that the
laboratory's actions were proper and invited Rae to lunch in an
effort to improve relationships.38

On 20 May, Garrett and Air Force officials met
again. Some changes in the description of work were made by mutual
consent. Garrett, willing to invest capital in developing Rex
engines, sought a development contract, but Appold rejected this as
untimely. Both parties, however, agreed on another matter: prompt
action to ensure an adequate supply of liquid
hydrogen.39

The government owned five acres of land within
Garrett's facility at Phoenix, and this was studied as a possible
site for a government-owned hydrogen liquefaction plant...

[130] Fig. 31. Rex I and
II engine systems as proposed by Rae in 1955. The Rex I engine, first
proposed in 1954, drove a two-stage air compressor and the air
expanded through the exhaust nozzle for propulsive thrust. In the Rex
II system, fuel was added to the airstream. Rex II was a form of
turborocket that had been studied in Germany, England, and the U.S.
in the 1940s. From R.S. Rae, "Various Engine Cycles Using Hydrogen as
a Working Fluid and as a Fuel," Twelfth Annual Flight Propulsion
Meeting, Institute of Aeronautical Sciences, Cleveland, 14 Mar.
1957.

....for Garrett's experimental needs. In June,
William C. Meister, a government Industrial specialist, reported that
the site was satisfactory. He also reported that liquid hydrogen
plant details could be obtained "from standard plants built in the
past."40 He was probably thinking of the Bureau of Standards
plant at Boulder or possibly the earlier Herrick L. Johnston plants,
but none of these was "standard."

On 6 June the persevering Rae tried again to
obtain acceptance of his original proposal for a complete airplane
development but failed once more. The meeting ended with three
unresolved issues: airframe work, Use of hydrogen in conventional
engines, and burning hydrogen in an afterburner, as proposed in
RexII.41 On 27 June, Rae's frustrations must have reached the
breaking point for in a meeting with Wright

[131] Fig. 32. Rex III
engine system. Heat from burning hydrogen with air is transferred by
means of heat exchangers to hydrogen on its way to the combustion
chamber. The heated hydrogen drives turbines prior to combustion.
There are three heat exchangers and three turbines. The turbines
power a two-stage air fan or compressor. After leaving the last
turbine, the hydrogen is injected and burned in the airstream in the
afterburner and the expansion of the hot gas through the nozzle
produces thrust. From R.S. Rae, "Various Engine Cycles Using Hydrogen
as a Working Fluid and as a Fuel," Twelfth Annual Flight Propulsion
Meeting, Institute of Aeronautical Sciences. Cleveland. 14 Mar.
1957.

....Field officials, including a judge
advocate, he refused to sign a contract with the Air Force, claiming
that it neglected his patent rights.*

Meanwhile, individuals in other organizations
were becoming interested in hydrogen. Silverstein of NACA had
completed his analysis in April 1955 and....

....according to one Air Force observer, "took
to the road" making a circuit of high-level Air Force officials. One
of these was Lt. Gen. Thomas Power, commander of the
ARDC.42 On 7 July, Power and Geri. Marvin Demler were briefed
by WADC on the Rex program, with results that became evident from
Appold's actions the following day. In discussions with his staff,
Appold expressed concern about the Rex program, asked questions about
the approach, the scope, and whether to go forward or cancel. He
asked for a recommendation based on a comparison between the Rex and
conventional engines available in the same time.43 On 16 July, ARDC authorized WADC to study
high-altitude engines with a two-pronged approach. One was to use
conventional engines and the other, a new propulsion system for
altitudes to 30 500 meters.44 This essentially reiterated the ARDC directive of the
previous year, but the sense of urgency had increased.

During July and August 1955, negotiations with
Rae and Garrett continued without much success. On 25 August, Rae
again refused to sign a contract, citing the inclusion of a study
task as his reason. According to the notes of Frank Patella of the
power plant laboratory who attended the meeting, Rae's position was:
"The Garrett Corporation wants a development contract at this time
and will not go along with anything less." Finally, however, after
much additional negotiation and revision of work statements, two
contracts with Garrett were signed in October 1955. One, coming from
PR 303, was not far from what the power plant laboratory had
originally specified. The other, from PR 339, was to study liquid
hydrogen tanks. The two totaled $3 284 000-over four times the
combined amount of the United Aircraft and Beech Aircraft contracts
that had been in effect since June.45

[133] When the Rex
division of Garrett received its two contracts from the Air Force,
after five months of hard negotiating, there was a big party and
celebration. The staff was confident that they were at last firmly on
the road to engine development and a great
future.46 Yet this was not to be, for the contract contained
provisions that were to eventually knock Garrett out of the major
competition.

* On the same day,
Raeís attorney filed a patent application of a mulistage,
high-altitude engine with a single combustion stage 9518049). On 18
Oct. 1960, he was granted patent 29256 402 for Rex III.